General English


  • The generic name for cheese in Balkan and some Slav countries

Cars & Driving

  • acronym forsupplementary inflatable restraint
    (written as SIR)
  • noun an air bag.


  • acronym forself-insured retention
    (written as SIR)


  • acronym forsurface insulation resistance
    (written as SIR)
  • acronym forsignal-to-interference ratio
    (written as SIR)
  • acronym forserial infrared
    (written as SIR)
  • A technology for providing a connection between devices supporting the use of infrared signals to convey information. Also, a device utilizing this technology. Its abbreviation is SIR.
  • The electrical resistance between two conductors separated by an insulator under specified electrical and environmental conditions. Its acronym is SIR.

Origin & History of “sir”

In common with many other European terms of address for men (such as monsieur and señor), sir goes back ultimately to Latin senior ‘older’ (source also of English senior). This was reduced in vulgar Latin to *seior, which found its way into Old French as *sieire, later sire. English borrowed this as sire (13th c.), which in weakly-stressed positions (prefixed to names, for instance) became sir. Other titles based on senior that have found their way into English include French monsieur (15th c.) (literally ‘my sire’), together with its plural messieurs (17th c.), abbreviated to messrs (18th c.); French seigneur (16th c.); Spanish señor (17th c.); and Italian signor (16th c.).

Surly (16th c.) is an alteration of an earlier sirly ‘lordly’, a derivative of sir. The meaning ‘grumpy’ evolved via an intermediate ‘haughty’.